In general, a vehicular lamp may switch between a low beam and a high beam. The low beam illuminates an area close to the vehicle with predetermined illuminance, regulations on light distribution are provided so that the low beam does not cause glare to an oncoming vehicle or a preceding vehicle, and the low beam is mainly used when a vehicle travels in an urban area. Meanwhile, the high beam illuminates a front wide region and a distant area with comparative high illuminance, and the high beam is mainly used when the vehicle travels at a high speed on a road where a few oncoming vehicles or preceding vehicles travel. Therefore, although the high beam provides higher visibility to a driver than the low beam, there is a problem in that the high beam causes glare to a pedestrian or a driver in a vehicle present in front of the vehicle.
Recently, there has been proposed an adaptive driving beam (ADB) technology which dynamically and adaptively controls a light distribution pattern of the high beam in accordance with a peripheral state of a vehicle. The ADB technology detects the presence or absence of a preceding vehicle, an oncoming vehicle, or a pedestrian in front of the vehicle, and reduces illuminance in respect to the region corresponding to the preceding or oncoming vehicle or the pedestrian, thereby reducing the glare to be caused to the preceding or oncoming vehicle or the pedestrian.
As a type of implementing the ADB function, there have been proposed, for example, a shutter type for controlling an actuator, a rotary type, and an LED array type. The shutter type or the rotary type may continuously change the width of an OFF region (light shielding region), but the number of OFF regions is limited to one. The LED array type may set a plurality of OFF regions, but the LED array type is discrete because the width of the OFF regions is limited to a light emitting width of LED chips.
The present applicant has proposed a scanning type as the ADB type capable of solving the aforementioned problems (see, e.g., Japanese Patent Laid-Open Publication No. 2012-224317). The scanning type forms a desired light distribution pattern in front of a vehicle by causing light to be incident on a rotating reflector (blade), reflecting the incident light at an angle in accordance with a rotational position of the reflector, scanning the reflected right in front of the vehicle, and changing ON/OFF or a light quantity of a light source in accordance with the rotational position of the reflector. See, for example, Japanese Patent Laid-Open Publication No. 2008-205357 and International Patent Publication WO2016/167250 A1.